Histological and histochemical study of the uropygial gland of chimango caracara (Milvago chimangovieillot, 1816)

Abstract

The uropygial glands of birds are sebaceous organs that contribute to the water-repellent properties of the feather coat. We studied the histological and histochemical characteristics of the uropygial gland of chimango caracara using hematoxylin and eosin (H & E), Gomori´s trichrome, orcein, Gomori´s reticulin, periodic acid-Schiff (PAS), Alcian blue (AB) and a variety of lectins. The gland is composed of two lobes and a papilla with 20 downy feathers. It is surrounded by a capsule of dense connective tissue that contains elastic, reticular and smooth muscle fibers. The papilla is delicate and has two excretory ducts. The gland mass relative to body mass was 0.143%. Both adenomer cells and their secretions were stained with Sudan IV, PAS and AB, and were positive for numerous lectins that indicated the presence of lipids and carbohydrates. Immunohistochemical techniques to detect PCNA confirmed cell proliferation in the basal stratum of the adenomer cells. The lipids and glycoconjugates secreted by the uropygial gland serve numerous functions including protection against microorganisms.

The uropygial gland of the Southern Caracara (Caracara plancus; Falconidae: Falconinae): histological and histochemical aspects

“…The histochemistry and lectin histochemistry analysis showed a variety of glycoconjugates as part of the uropygial gland, highlighting the complexity of the chemical composition of secretions. These results coincide with those performed in the uropigial gland of Chimango Caracara (Chiale et al 2015) and Mallard Anas plathyrhynchos (Kamiya et al 1986). Other studies found PAS positivity in the basal stratum and the uropygial secretion but in a homogeneous pattern, showing no division between a glycogen and sebaceous zones (Montalti et al 2001;Chiale et al 2014Chiale et al , 2015.…”

“…Birds with less contact with water have a large primary chamber, whereas aquatic birds such as penguins or skuas only have secondary chambers that lead directly to the external openings in the papilla (Chiale et al 2014). Other studies found PAS positivity in the basal stratum and the uropygial secretion but in a homogeneous pattern, showing no division between a glycogen and sebaceous zones (Montalti et al 2001;Chiale et al 2014Chiale et al , 2015. The histochemistry and lectin histochemistry analysis showed a variety of glycoconjugates as part of the uropygial gland, highlighting the complexity of the chemical composition of secretions.…”

“…The shape is as has been described by Johnston (1988) for this species. The uropygial gland of the Southern Caracara has a primary chamber or cavity, and this structure is also present in other bird species (Jacob and Ziswiler 1982;Harem et al 2010;Kozlu et al 2011;Chiale et al 2015). The uropygial gland of the Southern Caracara has a primary chamber or cavity, and this structure is also present in other bird species (Jacob and Ziswiler 1982;Harem et al 2010;Kozlu et al 2011;Chiale et al 2015).…”

“…This gland is surrounded by a capsule of dense connective tissue, and the parenquima is formed by tubular adenomers (Jacob and Ziswiler 1982;Sawad 2006;Kozlu et al 2011;Chiale et al 2014). The papillae have abundant dense connective tissue with reticular and elastic fibres surrounding the excretory ducts; the presence of smooth muscular fibres is associated with the follicles of the tuft feathers, and some may be distributed within the connective tissue (Chiale et al 2015). The papillae have abundant dense connective tissue with reticular and elastic fibres surrounding the excretory ducts; the presence of smooth muscular fibres is associated with the follicles of the tuft feathers, and some may be distributed within the connective tissue (Chiale et al 2015).…”

“…According to Lucas and Stettenheim (1972), the adenomers can be divided into three zones depending on the epithelial height and lumen width: Zone I, Zone II and Zone III. The papillae have abundant dense connective tissue with reticular and elastic fibres surrounding the excretory ducts; the presence of smooth muscular fibres is associated with the follicles of the tuft feathers, and some may be distributed within the connective tissue (Chiale et al 2015).…”